A 38-year-old manual worker has aching right forearm pain with tingling over the thumb, index, middle finger AND the skin over the thenar eminence. Symptoms are provoked by repetitive pronation rather than by sleep. Which single finding distinguishes his condition from carpal tunnel syndrome?
- A Involvement of sensation over the thenar eminence ✓
- B Weakness of abductor pollicis brevis
- C Tingling in the index finger
- D Preservation of the triceps reflex
Correct answer: A. Involvement of sensation over the thenar eminence
Explanation
He has pronator syndrome, median nerve compression between the heads of pronator teres. The palmar cutaneous branch of the median nerve arises proximal to the flexor retinaculum and passes superficially, so it is spared in carpal tunnel syndrome but affected in proximal median lesions. Sensory loss over the thenar eminence therefore excludes carpal tunnel syndrome and points to compression at the forearm level.
Reference: Snell's Clinical Anatomy by Regions, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.